Steam trap



Feb. 7, 1961 Filed Oct. 22, 1957 Fig. l

CHIYOMATSU MAEDA STEAM TRAP 2 Sheets-Sheet l If fll lha INVENTORATTORNEY Feb. 7, 1961 CHIYOMATSU MAEDA 2,970,603

STEAM TRAP Filed Oct. 22, 1957 2 Sheets-Sheet 2 INVENTOR ATTORNEY .nitedStates Patent STEAM TRAP Chiyomatsu Maeda, 2-158 Hamakoshien,Nishinomiya, Hyogo, Japan Filed Oct. 22, 1957, Ser. No. 691,583 Claimspriority, application Japan Apr. 17, 1957 8 Claims. (Cl. 137-194) Thisinvention relates to steam traps especially adapted for use in powerplants and serves as a means for separating liquid from steam anddischarging it into a reservoir, the main object of the invention beingto provide a construction wherein variations in steam pressure will havesubstantially no effect upon the operation of the trap.

Another object of the improvement is to produce a simple, effective andconvenient device for the purpose stated.

To this end the invention consists in the novel construction,arrangement and combination of parts shown and described, and moreparticularly pointed out in the claims.

In the drawings, wherein like reference characters indicate like orcorresponding parts;

Figure 1 is a transverse vertical section taken centrally of a deviceembodying the principles of the in vention;

Figure 2 is a plan view of the device, and;

Figure 3 is a transverse horizontal section on line 3-3 of Figure l withparts omitted.

As shown in the drawings, and referring particularly to Figure 1thereof, the illustrated trap 10 has a shell or casing 11 ofsubstantially cylindrical form adapted to be used with its axis upright.It is closed at the upper end by means of an integral end plate 12 overwhich is secured an upper cover member 14 as by means of suitable bolts14'. In one side, near the top of the trap casing, is an inlet 17 towhich is secured a part of the return line piping through which air,water of condensation, and exhaust steam flow from pipe lines. In theopposite side of the trap casing, near the bottom thereof, is the outlet18 which in the construction shown is formed as part of a lower covermember which closes the open bottom end of the trap casing and to whichit is secured by means of suitable bolts 19. The lower cover member 15includes an integral end plate 13 which serves to close the open bottomend of the casing 11. The casing 11 is thus divided into three verticalchambers, namely, an upper chamber 41, a middle chamber 42, and a lowerchamber 43, the end plates 12 and 13 serving as partition walls betweenthe chambers.

At the bottom of the casing the lower end plate 13 is provided with acentral aperture 13' which has fitted therein the removable valve seatmember 26. The valve seat member 26 is provided with a centrallydisposed valve port 26'. At the top of the casing the upper end plate 12is provided with a central opening 12' in which is fitted a verticaldrain pipe 27 fixed in place by means of a collar 27'. The upper end ofdrain pipe 27 is formed to provide a valve seat member 25 having a valveport 25' and the arrangement of parts is such that the upper and lowervalve ports 25' and 26' are in alignment. Directly above the upper valveport an adjustable stop member 28 is provided. Member 28 may be a boltfixed to the upper cover member 14. 7

2,970,603 Patented Feb. 7, 1961 A balanced discharge valve cooperateswith the ports 25' and 26' and comprises a cone shaped upper valveelement 22 adapted to control the upper port 25 and a cone shaped lowervalve element 23 adapted to control the lower port 26'. These valveelements are made of the same size and shape, so that diameter d equalsdiameter d The valve elements are interconnected by means of a stem 24which is disposed within the vertical drain pipe 27 in coaxial relationtherewith. The balanced valve, comprising the stem 24 and the valveelements 22 and 23, is secured to a float 31 by connecting pieces 32projecting from the stem 24 near the bottom of the stem. The lower endof the drain pipe 27 terminates at a point above the bottom end plate 13so that the lower part of the valve stem 24 is exposed to permit free upand down movement of the connecting pieces 32.

As shown, the float 31 is annular in form to accommodate within itscentral hole the vertical drain pipe 27 and the balanced valve.

A plurality of vertical pipes 21 are provided, arranged within the steamtrap casing symmetrically relative to the float and externally thereofas indicated in Figure 3. These pipes, which may be termed equalizingpipes, provide communication at all times between the upper chamber 41and the lower chamber 43 as shown in Figure l. The lower ends of thepipes are screwed into the lower end plate 13 while the upper ends ofthe pipes 21 are attached to upper end plate 12 by peening the upperends thereof as seen in Figure 1. The trap casing 11 is also providedwith a buffer plate 16 which is located adjacent the inlet 17 and avalve cock 29 for expelling air from chamber 42. The operation of thesteam trap is as follows:

The trap is installed vertically as shown in Figure 1 with the unit tobe drained connected to the inlet 17 and with the flanged outlet 18attached to a pipe leading to a suitable drain device. Exhaust steamcontaining the condensate flows into the middle chamber 42 through inlet17. As the steam flows into the trap it will be instantly separated fromthe condensate, the steam remaining in the upper part of the middlechamber and the condensate flowing by gravity into the bottom of themiddle chamber. Indicated pressure in the middle chamber isapproximately the same throughout. Normally, the upper valve 22 isseated upon its valve seat and the lower valve 23 is seated upon itsvalve seat. The steam pressure within the middle chamber 42 acts uponthe under surface of the upper valve 22 and upon the upper surface ofthe lower valve 23 equally because as already described both top andbottom valves are identical in shape and size with equal diameters d andd At this time the pressure within the upper chamber 41 acting on theupper surface of the upper valve 22 is the same as the pressure withinthe lower-chamber 43 acting upon the lower surface of the bottom valve23. The pressure within the upper and lower chambers is the same sincethey are in communication by the several equalizer pipes Accordingly,the valves are free from any effect of the pressure even though thesteam pressure in the trap may be high or low and even though thedifference of pressure between the middle chamber and either the upperor lower chamber may vary. Furthermore, the float 31 will not beaffected by variations in the steam pressure. Therefore, the valves 22and 23 will bear down upon their respective valve seats 25 and 26 withonly the weight of the float 31 and its attachments.

As the amount of condensate increases and the float is submerged thefloat will become more buoyant. When the buoyancy exceeds the weight ofthe float and its attachments, the float will rise giving the lift tothe upper and lower valves, allowing the condensate in the middlechamber=to"discharge' from -the upper and lower cham 'bers 43 throughthe valve openings. ,P,ressur.e vin the middle chamber 42 forcescondensate up through the drain pipe 27 and out through the upper valveport 25'. Steam, however, will 'beheld tightly; in the .middle .chamher.

As the action continues, the :condensate in=the middle chamberdecreases, the buoyancy of the float decreases also, until the buoyancybecomes less than'the weight of the float itself. Then the float fallsand the valves come into close contact with the valve seats againand thedischarge of thecondensate is cut ed.

The trap may be utilized in various types of steam lines, including highandlow pressure systems vand the functioning of the trap is not.aflected by changes of atmospheric temperature throughout the year.

Various modifications can be made :in the-em;b,odiment 'of the trapdescribed :above withoutxdeparting from the spirit of the invention, thescope of vwhich is inclicated by the following :claims.

I claim:

1. A steam trap comprising accasing having inlet and outlet openings.upper and lower horizontal partitions dividing said casing into an upperchamber, a middle chamber and a lower chamber, said inlet opening leading into .said middle chamber, said outlet opening leading from saidlower chamber, a balanced valve assembly in said casing, said valveassembly forming parallel flow paths comprising an upper valveseat in,said upper horizontal partition and a lower valve :seat in said lowerhorizontal partition, a balanced valve. cooperating with said valveseats, a float connected to said balanced valvehaving buoyancy withrespect to a liquid level in said middle chamber, a drain pipeextendingdownwardly from said upper valve seat to a point spaced froinsaid lowervalve seat for passing the liquid therethrough when pressure applied tosaid liquid level is greater than the liquid head required to fill saiddrain pipe, and at least one pressure equalizing pipe providingcommunication between saidupper and lower chambers.

2. A steam trap as set forth in claimtl, iniwhich the valves'are of thesame'shape and dimensions.

3. A steam trap as set forth in claim l,-in which the valves are coneshaped-and of equal area in horizontal cross section.

4. A steam trap asset forth in claim .3, in which the upper chamber hasa limit'stop above-the gupper valve for limiting its upwardrmovement.

5. A steam trapxas set forth in claim, 1 ,in which the casing iscylindrical, the float is annular in ?form and coaxial with thecylindergythe .drain pipe is withinthe .float and-coaxial therewith,thexvalve assembly is within the drain pipe and coaxial therewith,:andin which the pressure equalizing pipes are disposed in symmetrical arrayabout the central vertical'axis'ofthe casing.

.end of the drain pipe.

7. A steam trap comprisinga casing; partitions dividing said casingintoupper, middleand lower chambers;

said ".casingthaving an inlet to said middle'chamber-and anoutlet fromsaid lower and upper chambers; afloat in .said middle chamber: valveseats in said upper and lower partitions; balanced valves closing saidvalve seats, said balanced valves being opened by upward movement ofsaid float ll'l response to a rise of liquid level in said middlechamber and being closed by downward movement of said float in responseto a lowering of liquid level in said middle chamber; and a drain pipeextending from the valve seat ;in said upper partition to a level insaid middle chamber below a level of vliquid therein at whichsaidbalanced valve begins to open; the rise of the liquid level in saidmiddle chamber opening said balanced valves to'provide flowvof liquidthrough the valve seat insaid lower partition even when only the forceof gravity actsupon the liquid and provide flow of liquid alsothrough=the .valvegseat in said upper partition when pressure applied tothe liquid produces a liquid head in excess of that required for fillingthe drain pipe and the valve seatin said upper partition.

=8. ,Asteam trap. comprisingacasing having inlet and outlet openings,said inlet opening capable of receiving liquid and steam under pressure,upper and lower partitions dividing said casing into an upper chamber, amiddle chamber and a lower chamber, said inlet opening leading into saidmiddle chamber and said outlet opening leadingfrom said lowerchamber, asbalanced valve assembly forming parallel flow paths'from the inletopening to the outlet opening including an upper valve seat in saidupper partition and a lower .valve seat in said lower partition andincluding a balanced valve cooperating with said valve seats-for closingsaid parallel flow paths, a float responsive to a quantity of liquid insaid middlechamber and connected to said balanced valve for opening saidparallel flow paths when the liquid level intherniddle chamberreaches alevel causing the float-to become buoyant, a drain pipeextendingdownwardly from said upper valve seat to a point below said level, anda-pressure equalizing pipe providing passage of liquid between saidupper and lower chambers, said liquid on opening of said balanced valvebeing passed through the lower valve seat in the absence of steampressure in the middle chamber sufficient to produce the liquid headto-fill said drain pipe, and said liquid on opening ofsaidbalancedvalvebeing passed through both valve seats in the presence ofsteam pressure in the middle chambergreater than the liquid headrequired to fill said drain pipe, which greater pressure during itscontinuation forces the liquid through the drainpip e, the upper valveseat, and theequalizing pipeto the-outlet opening.

References'Cited in the file of this patent UNITEDSTATES PATENTS 193,938Edwards Aug. 7, 1877 2,043,074 Simpson June 2, 1936 2,349,938 BurnetteMay 30, 1944 2,648,347 Fahnoe Aug. 11, 1953 FOREIGN PATENTS 763 G rm yv----r--.--.---iy 2 1894 679,526 Germany Aug.v 8, 1939

